September 1952 E-847
01 United States Department of Agriculture
Agricultural Research Administration
Bureau of Entomology and Plant Quarantine
PRELIMINARY SCREENING OF
EMULSIFIABLE TOXAPHENE CONCENTRATES^
B. I. Sparr^
Division of Insects Affecting Man and Animals
In the application of toxaphene emulsions by power spraying, the
stability of the emulsion presents only a minor problem. However,
where the stock is dipped in a vat the stability of the emulsion is of
major importance. Experiments were therefore conducted to develop
emulsifiable toxaphene concentrates that would yield stable emulsions.
A method for screening candidate concentrates containing different
emulsifiers is described, and the results of screening some formula-
tions are reported. Another consideration was the use of agricultural
products in insecticide formulations; hence the testing of turpentine and
pine oil as solvents.
Three types of formulations were tested:
(1) Three experimental concentrates containing 50 percent of toxa-
phene, 10 percent of emulsifier, and 40 percent of one of the following
solvents: kerosene, pine oil (sp. gr. 0.9358 at 15.6°/ 15.6° C), or
turpentine (all percentages by weight).
(2) Three commercial concentrates:
(A) Toxaphene 65, aliphatic hydrocarbon solvent 25, alkylaryl
poplyethylene glycol 7.5, and alkylaryl sulfonate 2.5 percent.
1/ Report of a study made under the Research and Marketing Act of
2/ The author is indebted to H. F. Beckman, R. C. Bushland, H. V.
Claborn, and R. D. Radeleff for advice and occasional assistance in these
- 2 -
(B) Toxaphene 60, aliphatic hydrocarbon solvent 22, aromatic
hydrocarbon solvent 5, alkylaryl polyethylene glycol 5, poly-
ethylene glycol ester 5, and polyoxyethylene sorbitol oleate-
laurate 3 percent.
(C) Toxaphene 50, alkylaryl polyethylene glycol 4, phthalic
glycerol ajkyd resin 6, epichlorhydrin 0.2, and petroleum
(3) A miscellaneous group of formulations suggested by various
The specific gravities at 25° C, of the solutions of toxaphene in the
experimental concentrates were determined, and for this work were con-
sidered as constant with respect to temperature. The volume containing
5 grams of toxaphene for each solution was used for making the test
Preparation of Emulsions
The following procedure was adopted for preparing the emulsions:
One gram of emulsifier was weighed into a 50-ml. beaker. The
volume of the kerosene, pine oil, or turpentine solution containing
5 grams of toxaphene was pipetted into the beaker and the mixture
stirred to dissolve the emulsifier. When necessary, gentle heat was
applied. Distilled water was then added slowly until an oil-in-water
emulsion was formed. This emulsion was poured into a 500-ml. grad-
uated cylinder and diluted with distilled water to 500 ml. to produce a
1 -percent toxaphene emulsion. It was then poured into a 1 -liter
Erlenmeyer flask, stoppered, and shaken for 30 seconds. Into each
of five calibrated vials, 9.7 cm. long and 2.4 cm. inside diameter,
15 ml', of the freshly shaken emulsion was poured. The emulsion was
further diluted to contain 0.5 percent of toxaphene by adding to each vial
an equal volume of distilled water, tap water (containing 14 grains of
calcium carbonate per gallon), 2-percent acetic acid, ammonium
hydroxide, or sodium chloride. The vials were placed in racks and left
open to the air.
Observations and Screening Criteria
The emulsions were examined after 1 hour, 1 day, and 1 week.
Observations were made on the extent of bottom creaming as measured
with a millimeter rule, the degree of top clearing, any phase separation,
the ease of re-emulsification of the separated oil or ease of resuspension
of the cream, and the discernibility of resuspended particles when the
vials were illuminated by flashlight.
Since for use in dipping vats a stable emulsion with a slow rate of
creaming was desirable, the following criteria were established for
choosing the more promising formulations:
(1) The emulsifier was soluble in the toxaphene solution.
(2) No bottom creaming, or only a trace, appeared in any vial at
the end of a week.
(3) There was no oil separation in any of the aqueous media, except
the 1 -percent sodium chloride system, at the end of a week.
(4) The cream was readily redispersed on inversion of the vial.
(5) Upon illumination of the vial after inversion, there were no
individually discernible particles.
(6) There was either no top clearing or only slight clearing,
Since no pine-oil concentrates conformed to criterion (2), the pine-
oil emulsions chosen for further consideration showed 1 mm. or less
of bottom creaming, but met the other criteria.
Experimental concentrates . --In the course of testing the experi-
mental concentrates 103 emulsifiers were tried. The following were
found to give satisfactory formulations with at least one type of toxa-
phene emulsion, according to the criteria outlined above.
Ahco RL 382 (Arnold, Hoffman & Co.) Kerosene
Ahcowet Anhydrous RS (Arnold,
Hoffman & Co.) --------------- Kerosene and turpentine
Antarox D-100 (General Dyestuff Corp.) - - - Pine oil
Chlorsol (E.F. Drew & Co.) --------- Pine oil and turpentine
Duponol G (E.I. du Pont de Nemours & Co.) - Kerosene
Emcol H-77 (Emulsol Corp.) Pine oil
Emulside 75 (Van Dyk & Co.) -------- Kerosene
Emulsifier 803-M (E. F. Drew & Co.) Turpentine
Emulsifier R (Monsanto Chemical Co.) - - - Kerosene
Nopco Agrimul 60 (Nopco Chemical Co.)- - - Kerosene and turpentine
Nopco 1219-A (Nopco Chemical Co.)- - - - - Kerosene
Nopco HBX-2 (Nopco Chemical Co.) ----- Kerosene
Skil 181 -A (Gallowhur Chemical Corp.) - - - Kerosene
Tenlo 400 (Griffin Chemical Co.)- ----- - Kerosene and turpentine
Trex 45 (Griffin Chemical Co.)-------- Turpentine
Trex 80 (Griffin Chemical Co.) Turpentine
The kerosene-type concentrates containing Emulsifier R, Tenlo 400,
or Duponol G were stable in 1 -percent sodium chloride solution for a
week. Many of the concentrates that did not meet these criteria may be
suitable for other purposes, such as use in sprays.
Commercial concentrates . --The amounts of bottom creaming in
emulsions prepared from the three commercial concentrates after they
had stood for 7 days are shown below.
1 mm .
2 mm .
3 mm .
Emulsions A and C showed nearly complete top clearing and particles
were discernible upon resuspension.
It is apparent that concentrates A and C do not meet the criteria
established. Except for extent of creaming, concentrate B does meet
This report does not constitute a condemnation of any of these prod-
ucts. Two of them are being used extensively and successfully in Texas,
although there have been reports (Radeleff and Bushland 1950) of cattle
killed by dipping in vats in which such emulsions had deteriorated.
Miscellaneous formulations. --Of 23 miscellaneous formulations
tested, 19 were either recommended by emulsifier producers or supplied
by them for evaluation; the remaining 4 were arbitrarily compounded in
the laboratory. Formulations containing the following emulsifiers and
solvents were found to be satisfactory.
Deodorized kerosene 15
Butyl Cellosolve 15
G-89K. 1 (Atlas Powder Co.)
All formulations except those containing Antarox A- 200 or Ahco
RL-382 formed solubilized systems when diluted with water. The
degree of transparency varied, but the most opaque materials showed
no sign of creaming at the end of a week in the vials. Formulations
containing Ahcowet RS and Ahco RL-382 broke in 1 -percent sodium
Experiments in miniature vats . --The validity of this method for
selecting formulations for further development has been supported by
two experiments conducted in miniature (7 -gallon) concrete dipping vats.
In the first experiment - ^ four formulations prepared in the laboratory and
two commercial concentrates (A and C) were used. Under similar con-
ditions of vat-charging methods, climate, contamination, and time, the
laboratory-prepared formulations showed less deterioration than the
Two of the miscellaneous solubilizable concentrates were included
in these tests. Although they showed no oil separation or gumminess,
one of them developed a thick pellicle at its surface. The other concen-
trate showed evidence of creaming, but upon agitation the cream was
These experiments indicate that certain combinations of emulsifier,
solvent, and toxaphene produce emulsifiable concentrates that are more
stable than some commercial formulations when diluted and held under
laboratory conditions. It is to be emphasized that most of the results
were obtained in laboratory glassware. The confirmatory tests with
emulsions held in miniature vats do not represent actual field observa-
tions. However, the formulations that performed better under those
limited experimental conditions merit further testing in ranch vats.
Radeleff, R. D. , and Bushland, R. C.
1950. Acute toxicity of chlorinated insecticides applied to livestock.
Jour. Econ. Ent. 43(3): 358-364.
3/ Conducted by R. D. Radeleff (unpublished report) .
UNIVERSITY OF FLORIDA
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